President Reagan is expected to inform Congress soon that he has postponed until later this year a decision on whether the United States will exceed limits on nuclear missiles in the unratified SALT II treaty, administration officials said yesterday.

Reagan is required by law to submit a report to Congress by Saturday on plans for complying with the treaty. One official said the report will discuss options but not include a decision by Reagan on whether the United States intends to exceed the treaty limits on missiles.

A second official said Reagan is still considering what to put in the report to Congress. This official said the report will probably be delayed beyond the June 1 deadline, in part to allow time for a National Security Council meeting on the decision.

Administration officials have been sharply divided about whether the United States should exceed the SALT II limits. White House spokesman Larry Speakes said yesterday that Reagan "has a number of options before him, and he may simply state to the Congress that these are the options that are now before us, and that we may not arrive at these decisions . . . until the fall."

The limits in SALT II, never ratified by the Senate, are to lapse at the end of the year. The superpowers have pledged since 1981 to continue respecting the treaty's main provisions.

Reagan must decide whether to exceed the limits this fall when the USS Alaska, a Trident submarine, begins sea trials, putting the United States above the SALT II limit for multi-warhead intercontinental ballistic missiles.

Administration officials said one reason for postponing a decision on the limits would be to allow time to see whether the Soviets shift from their hard-line positions at the second round of Geneva arms talks that begin this week.

Officials also said Reagan has decided to send Vice President Bush to reassure Western European leaders about Reagan's Strategic Defense Initiative, a proposed high-technology shield against incoming Soviet missiles.

In contrast to his high-profile effort to bolster Western European support for deployment of intermediate-range weapons in 1982, Bush is expected to consult privately with leaders in Britain, France, West Germany, the Netherlands and Belgium on this trip, officials said.

Reagan gave final instructions yesterday for the Geneva talks to chief negotiator Max M. Kampelman, and the White House accused the Soviets of "backtracking" on previous positions in the negotiations.

Taking note of a statement by Soviet leader Mikhail Gorbachev that the first round of talks had been "fruitless," Speakes said, "Unfortunately, we find ourselves in agreement with this characterization, owing to Soviet backtracking . . . .

"We find the Soviet comments are an intriguing tactic for turning recalcitrance into a virtue," he added.

Officials said later that Speakes was referring to Soviet retreats from positions in strategic arms reduction talks during Reagan's first term.

"The U.S. returns to the negotaitions with hope," Speakes said, "if the Soviets are able to turn from their internal accounts to take advantage of the opportunity for progress." White House officials have said they think that Gorbachev is preoccupied with internal problems and not prepared to discuss a possible meeting with Reagan.

One official said some administration officials think that Gorbachev is seeking U.S. concessions in Geneva before deciding whether to meet with Reagan.

Speakes said the U.S. positions in Geneva have not changed and that the administration "will not reward the Soviets for backtracking" on earlier positions.